Saliva is a complex fluid with intriguing wetting behavior central to oral hygiene and lubrication, oral processing of food, and microbial defense. For example, in dental applications, the spreading behavior of saliva on implant materials is important for its improved long-term stability and success, and prevention of biofilm formation, whereas in virus-loaded saliva drops, the evaporation kinetics of the carrier droplet plays an important role in the viral lifetime. The importance of wetting, spreading, and evaporation of viral-loaded drops of biological fluids in disease transmission has become more evident since the pandemic.

We are carrying out studies on model biological fluids, including bulk and interfacial rheology, and wetting, spreading dynamics, and evaporation on various surfaces, to advance the understanding of key parameters at play in spreading/evaporation of biofluids. Moreover, since saliva often comes in contact with other surface-active species such as surfactants and nanoparticles (for example through oral products), and soft substrates (e.g., tissue, skin), the fundamental knowledge obtained through this research will serve as a base on our path to uncover the complex physics involved in such multicomponent fluidic system.